MLA

Wat, Aleksander, 1900-1967. Poems, holograph. Box 22, folder 464-470. undated. https://collections.library.yale.edu/catalog/2029935.

APA, 6th edition

Wat, Aleksander, 1900-1967. (["Box 22, folder 464-470"])(undated)[Poems, holograph]. https://collections.library.yale.edu/catalog/2029935.